The invention relates to an apparatus for producing and providing a vacuum for a vacuum consumer. The invention also relates to a ventilation valve.
Devices of this type for producing and providing a vacuum are used, for example, in vehicles for operating a brake booster. One problem is that when the vehicle is stationary and the engine is switched off, the vacuum in the brake booster slowly decreases due to leakage, in particular in the vacuum generator and up to the suction valve, approaching atmospheric pressure. As a result, the brake pedal cannot be moved when attempting to start the vehicle and hence the trigger point required for starting cannot be attained in vehicles with automatic transmissions, so that the vehicle cannot be started. Responsible is here the check valve upstream of the brake booster which, unlike the suction valve, does not have a return spring.
It is therefore an object of the invention to provide an apparatus and/or a ventilation valve which reduces the risk that the brake booster is slowly vented.